Liquid crystal display unit

ABSTRACT

A liquid crystal display device according to the present invention includes: a vertical alignment liquid crystal layer; first and second electrodes arranged on one surface of first and second substrates to face the liquid crystal layer; and first and second alignment films arranged on the first and second electrodes, respectively, in contact with the liquid crystal layer. The first alignment film has been subjected to an optical alignment treatment by obliquely irradiating a first alignment film material, having a photosensitive wavelength within the wavelength range of 250 nm to 380 nm, with light including the photosensitive wavelength. The device further includes: a metal layer arranged between the first alignment film and the first substrate; and a first resin layer arranged between the metal layer and the first alignment film. The first resin layer has an optical property that attenuates the intensity of light, which has been incident on the first resin layer and then reflected from the metal layer, to 60% or less at the photosensitive wavelength.

This application is a continuation of U.S. patent application Ser. No.12/088,034, filed 25 Mar. 2008, which is the U.S. national phase ofInternational Application No. PCT/JP2006/319298, filed 28 Sep. 2006,which designated the U.S. and claims priority to JP 2005-286033 filed 30Sep. 2005, the entire contents of each of which are hereby incorporatedby reference.

TECHNICAL FIELD

The present invention relates to a liquid crystal display device andmore particularly relates to a liquid crystal display device with a wideviewing angle characteristic.

BACKGROUND ART

Recently, the display performances of liquid crystal displays (LCDs)have been improved to the point that more and more manufacturers adoptLCD panels as TV monitors, for example. As a result of those researchesand developments, the viewing angle characteristic of LCDs has beenimproved to a certain degree but not satisfactorily in some respects.Among other things, there is still a high demand for improvement of theviewing angle characteristic of an LCD using a vertical alignment liquidcrystal layer (which is sometimes called a “VA mode LCD”). As usedherein, a “vertical alignment liquid crystal layer” refers to a liquidcrystal layer in which liquid crystal molecules are aligned so as tohave their axis form an angle of (i.e., have a pretilt angle of)approximately 85 degrees or more with respect to the surface of avertical alignment film. The liquid crystal molecules have negativedielectric anisotropy and the VA mode LCD is combined with polarizersthat are arranged as crossed Nicols to conduct a display operation in anormally black mode.

A VA mode LCD, which is currently used for a TV set with a big screen,for example, adopts a multi-domain structure in which multiple liquidcrystal domains are formed in a single pixel region, to improve theviewing angle characteristic. An MVA mode is often adopted as a methodof forming such a multi-domain structure. Specifically, according to theMVA mode, an alignment control structure is provided on one side of thetwo substrates, which face each other with a vertical alignment liquidcrystal layer interposed between them, so as to face the liquid crystallayer, thereby forming multiple domains with mutually differentalignment directions (i.e., tilt directions), the number of which istypically four. As the alignment control structure, a slit (as anopening) or a rib (as a projection structure) may be provided for anelectrode, thereby creating an anchoring force from both sides of theliquid crystal layer.

If a slit or a rib is adopted, however, the anchoring force will beapplied onto liquid crystal molecules non-uniformly within a pixelregion because the slit or rib has a linear structure unlike thesituation where the pretilt directions are defined by an alignment filmin a conventional TN mode LCD. As a result, the response speed may havea distribution unintentionally. In addition, since the transmittance oflight will decrease in the areas with the slits or ribs, the luminanceon the screen will decrease, too.

To avoid these problems, the VA mode LCD also preferably has amulti-domain structure by defining a pretilt direction with an alignmentfilm.

Examples of VA mode LCDs with an alignment control structure forcontrolling the pretilt directions with an alignment film include aVAECB (vertical alignment electrically controlled birefringence) modeLCD (see Patent Document No. 1, for example), an RTN (reverse twistednematic) mode LCD and a VATN (vertical alignment twisted nematic) modeLCD (see Patent Documents Nos. 2 to 5, for example).

In the VAECB mode LCD, the pretilt directions of liquid crystalmolecules, which are defined by two alignment films that face each otherthrough a liquid crystal layer, are antiparallel to each other in anarbitrary domain in a pixel. That is why the tilt direction of liquidcrystal molecules around the middle of the thickness of the liquidcrystal layer agrees with the pretilt direction defined by the alignmentfilm on the lower substrate. In this case, the tilt direction of thoseliquid crystal molecules is an azimuthal direction indicated by thearrow that represents the tip of the liquid crystal molecules pointingtoward the viewer when the LCD is viewed by the viewer. Also, the tiltdirections of the liquid crystal molecules are constant irrespective ofthe position in the thickness direction of the liquid crystal layer orthe magnitude of the applied voltage.

On the other hand, in the RTN mode, the pretilt directions of liquidcrystal molecules that are defined by the two vertical alignment filmsin an arbitrary domain of a pixel are substantially perpendicular toeach other. Also, in the RTN mode, when a sufficiently high voltage(which is at least equal to a signal voltage to display the highest grayscale) is applied to the liquid crystal layer, liquid crystal molecules,located around the center of a plane of the liquid crystal layer andaround the middle of the thickness of the liquid crystal layer, aretilted in a direction that substantially equally divides the two pretiltdirections defined by the alignment films into two.

Examples of known methods for getting the pretilt directions defined byvertical alignment films include a process that requires a rubbingtreatment and a process that requires an optical alignment treatment.Among other things, the optical alignment treatment can be done on thealignment films without making any physical contact with them. That iswhy unlike the rubbing treatment, the optical alignment treatment wouldproduce no static electricity and could increase the yield. Furthermore,as disclosed in Japanese Patent Application No. 2005-141846 that wasfiled by the applicant of the present application, by using an opticalalignment film including a photosensitive group that can form a bondstructure, the variation in the pretilt angle can be reduced to onedegree or less. As a result, the display luminance characteristic can beimproved.

However, the optical alignment treatment has its own problems.

For example, Patent Document No. 6 discloses a technique for reducingthe optical deterioration of an optical alignment film by arranging amember that absorbs UV rays between the optical alignment film that islocated closest to the viewer and the uppermost surface for the viewer.

On the other hand, Patent Document No. 7 discloses a technique forminimizing the disturbance in alignment treatment that would be causedby light reflected from a taper portion of a metallic electrode, whichis provided to produce a lateral electric field in a pixel, in asituation where the optical alignment treatment is adopted to fabricatean IPS mode LCD.

-   -   Patent Document No. 1: Japanese Patent Application Laid-Open        Publication No. 2001-281669    -   Patent Document No. 2: Japanese Patent Application Laid-Open        Publication No. 11-352486    -   Patent Document No. 3: Japanese Patent Application Laid-Open        Publication No. 2002-277877    -   Patent Document No. 4: Japanese Patent Application Laid-Open        Publication No. 11-133429    -   Patent Document No. 5: Japanese Patent Application Laid-Open        Publication No. 10-123576    -   Patent Document No. 6: Japanese Patent Application Laid-Open        Publication No. 2001-272682    -   Patent Document No. 7: Japanese Patent Application Laid-Open        Publication No. 2005-128359

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

The method disclosed in Patent Document No. 6 can be used effectively tominimize optical deterioration of an optical alignment film but cannotprevent its alignment treatment from being disturbed by light reflectedfrom an underlying metal layer when an optical alignment treatment isadopted to make a VA mode LCD with a multi-domain structure.

Meanwhile, the method disclosed in Patent Document No. 7 is effectivelyapplicable to an IPS mode LCD, but not to a VA mode LCD. The reason isas follows. Specifically, an IPS mode LCD conducts a display operationby getting liquid crystal molecules aligned by a lateral electric fieldgenerated between metallic electrodes in a pixel, and therefore, doesnot use areas on those electrodes for display purposes. On the otherhand, a VA mode LCD conducts a display operation by using an electricfield generated between electrodes that are located over and under aliquid crystal layer, and therefore, can apply a predetermined voltageto every area within a pixel and can use basically the entire pixel fordisplay purposes. That is why if the manufacturing process of a VA modeLCD included an optical alignment treatment, then light reflected form ametal layer under an optical alignment film (including lines orelectrodes made of the metal layer or an opaque layer) would disturb thealignment treatment, thus eventually debasing the display quality.Hereinafter, this problem will be described with reference to FIG. 4.

Optical alignment films may be roughly classified into the following twotypes according to their mechanisms of producing anchoring force thatdefines the pretilt direction of liquid crystal molecules. One is anoptical alignment film that uses a polarized UV ray and producesanchoring force either parallel or perpendicularly to its polarizationdirection. The other is an optical alignment film to be irradiatedobliquely with light and to produce anchoring force in a directioncorresponding to the direction that the light has come from. In thelatter case, however, the incoming light only needs to be incident onthe film obliquely and may be polarized in some cases. For example, aP-polarized ultraviolet ray may be incident on the film so as to form anangle of incidence of 20 to 60 degrees (with respect to a normal to thefilm plane) as will be described later.

In the latter optical alignment film, the direction in which theanchoring force is produced is defined by the direction in which thelight is coming in the optical alignment treatment. That is why inmaking such an optical alignment film, if an optical alignment filmmaterial film 46 that has been deposited so as to cover a metal layer 42on a substrate 40 were irradiated obliquely with light LI including thephotosensitive wavelength of the optical alignment film material, thenthe light LR reflected from the metal layer 42 would enter the opticalalignment film material film 46 again and would affect its property.More specifically, since the direction in which the reflected light LRenters the optical alignment film material film 46 is different from thedirection of the incoming light LI, the anchoring force would beproduced in non-uniform directions and the liquid crystal moleculescould not be aligned in a predetermined pretilt direction in the areasirradiated with the reflected light LR. The methods disclosed in PatentDocument Nos. 6 and 7 cannot resolve this problem.

In order to overcome the problems described above, the present inventionhas an object of providing a VA mode liquid crystal display device thatwould not have its alignment state disturbed even if its manufacturingprocess included an optical alignment treatment.

Means for Solving the Problems

A liquid crystal display device according to the present inventionincludes: a vertical alignment liquid crystal layer; first and secondsubstrates that face each other with the liquid crystal layer interposedbetween them; a first electrode, which is arranged on one surface of thefirst substrate so as to face the liquid crystal layer, and a secondelectrode, which is arranged on one surface of the second substrate soas to face the liquid crystal layer; and a first alignment film, whichis arranged on the first electrode so as to contact with the liquidcrystal layer, and a second alignment film, which is arranged on thesecond electrode so as to contact with the liquid crystal layer. Thefirst alignment film has been subjected to an optical alignmenttreatment by obliquely irradiating a first alignment film material,having a photosensitive wavelength within the wavelength range of 250 nmto 380 nm, with light including the photosensitive wavelength. Thedevice further includes: a metal layer arranged between the firstalignment film and the first substrate; and a first resin layer arrangedbetween the metal layer and the first alignment film. The first resinlayer has an optical property that attenuates the intensity of light,which has been incident on the first resin layer and then reflected fromthe metal layer, to 60% or less at the photosensitive wavelength.

In one preferred embodiment, the first resin layer exhibits atransmittance of 90% or more with respect to light falling within thewavelength range of 400 nm to 800 nm.

In another preferred embodiment, the first resin layer hasphotosensitivity.

In still another preferred embodiment, the first resin layer has athickness of 1 μm to 5 μm.

In yet another preferred embodiment, the first alignment film has atleast two areas in a pixel, and the two areas give mutually differentpretilt directions to liquid crystal molecules.

In yet another preferred embodiment, the metal layer includes at leastone member selected from the group consisting of a gate bus line, asource bus line, a CS bus line and an opaque layer.

EFFECTS OF THE INVENTION

The present invention provides a VA mode liquid crystal display devicethat would not have its alignment state disturbed even if itsmanufacturing process included an optical alignment treatment. As aresult, the display quality and reliability of a VA mode liquid crystaldisplay device, having a multi-domain structure formed by an opticalalignment treatment, among other things, can be improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional view illustrating how an opticalalignment treatment process is carried out on a TFT substrate 10A foruse to make a VA mode LCD as a preferred embodiment of the presentinvention.

FIG. 2 shows the transmittance spectra Ta and Tb of two types of shortwave absorbing resin layers (films a and b).

FIG. 3 shows the emission spectrum IO of a light source for use in theoptical alignment treatment and the intensity spectra Ia′ and Ib′ of thereflected light with the films a and b, respectively.

FIG. 4 is a schematic representation illustrating a problem with aconventional optical alignment treatment.

DESCRIPTION OF REFERENCE NUMERALS 10 glass substrate 10A TFT substrate12 metal layer 14 short wave absorbing resin layer 15 pixel electrode 16optical alignment film

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a configuration for a liquid crystal display device as apreferred embodiment of the present invention will be described withreference to the accompanying drawings. In the preferred embodiment tobe described below, the present invention is implemented as TFT LCD.However, the present invention is in no way limited to such a specificpreferred embodiment but is applicable broadly to any other type of LCDwith a metal layer on one of its substrates.

FIG. 1 is a schematic cross-sectional view illustrating how an opticalalignment treatment process is carried out on a TFT substrate 10A foruse to make a VA mode LCD as a preferred embodiment of the presentinvention. FIG. 1 also schematically illustrates how liquid crystalmolecules are aligned in a predetermined pretilt direction by an opticalalignment film 16.

The TFT substrate 10A includes a glass substrate 10 and a metal layer12, which forms at least a part of a TFT (not shown), a gate line, asource bus line or a CS bus line that is arranged on the glass substrate10. A short wave absorbing resin layer 14 is further deposited so as tocover the metal layer 12. A pixel electrode 15 made of a transparentconductive layer (such as an ITO layer) is arranged on the short waveabsorbing resin layer 14. And an optical alignment film 16 has beendeposited over almost the entire surface of the substrate as well asover the pixel electrode 15. In this example, the film of an opticalalignment film material that has not been subjected to an opticalalignment treatment yet and the optical alignment film obtained by thetreatment will be identified by the same reference numeral for the sakeof simplicity.

The optical alignment film material to make the optical alignment film16 has a photosensitive wavelength within the wavelength range of 250 nmto 380 nm and is subjected to an optical alignment treatment by beingobliquely irradiated with light LI including the photosensitivewavelength. Specifically, the optical alignment film material absorbslight with the photosensitive wavelength and produces a chemicalreaction (such as decomposition or formation of chemical bonds) to be analignment film that produces anchoring force in a predetermineddirection.

As the optical alignment film material to be subjected to the alignmenttreatment by being obliquely irradiated with light, an optical alignmentfilm material including a photosensitive group with a photosensitivewavelength of 380 nm or less is preferably used as disclosed in JapanesePatent Application No. 2005-141846, which was filed by the applicant ofthe present application. The photosensitive group preferably forms abonding structure and includes at least one photosensitive groupselected from the group consisting of cinnamoyl group (I), coumaringroup (II), 4-carcone group (III) and 4′-carcone group (IV) asrepresented by Chemical Formula (I). The optical alignment film materialpreferably produces a photodimerization reaction when irradiated with anultraviolet ray. By adopting such an optical alignment film material andsetting the difference between the pretilt angles defined by a pair ofalignment films to one degree or less, the display luminancecharacteristic can be improved. The light to cast to get the opticalalignment treatment done is an ultraviolet ray with a photosensitivewavelength of 380 nm or less and is preferably a P-polarized ultravioletray. The angle of incidence on the alignment film (i.e., the angledefined with respect to a normal to the film plane) preferably fallswithin the range of 20 to 60 degrees, more preferably within the rangeof 30 to 50 degrees, and most preferably around 40 degrees.

In this preferred embodiment, the TFT substrate 10A includes the shortwave absorbing resin layer 14 between the optical alignment film 16 andthe metal layer (such as a gate bus line) 12. That is why the intensityof the reflected light LR that has entered the alignment film 16 againafter having been transmitted through the optical alignment film 16 andthen reflected from the metal layer 12 can be attenuated sufficiently.That is to say, the short wave absorbing resin layer 14 has such anoptical property as to sufficiently decrease the intensity of the lightwith the photosensitive wavelength that has entered the short waveabsorbing resin layer 14 and has been reflected from the metal layer 12.Consequently, even if the reflected light LR enters the opticalalignment film 16 again, the optical alignment film does notsubstantially change its properties and can exert the anchoring forcethat has been produced by an optical alignment treatment with the lightLI just as expected.

Hereinafter, the optical property that the short wave absorbing resinlayer 14 should have will be described in detail.

The light LI to shine on the film to get the optical alignment treatmentdone is usually an ultraviolet (UV) ray including light falling withinthe wavelength range of 250 nm to 380 nm. The UV ray LI that irradiatesthe optical alignment film (or more exactly, a film of the opticalalignment film material) 16 is partially absorbed into the opticalalignment film 16. On the other hand, the transmitted part of the UV rayLI is incident on, and reflected from, the metal layer 12 and thenenters the optical alignment film 16 again. Meanwhile, the light LI thathas been incident on the optical alignment film 16 over the pixelelectrode 15 made of an ITO layer enters the optical alignment film 16again after having been transmitted through the pixel electrode 15twice.

The optical alignment film 16 normally has a thickness of 0.5 μm to lessthan 1.0 μm and absorbs the incoming light little. Also, as the chemicalreaction advances upon the exposure to the light, the absorbance at thephotosensitive wavelength decreases. The ITO layer that is the materialof the pixel electrode 15 also absorbs an ultraviolet ray but sometimescannot reduce the intensity at the photosensitive wavelengthsufficiently. Furthermore, since the UV ray is cast obliquely, part ofthe UV ray may pass through the gap of the pixel electrode 15, bereflected from the metal layer 12, pass through either the gap of thepixel electrode 15 or the pixel electrode 15 itself, and then enter theoptical alignment film 16. Consequently, the optical alignment film 16is seriously affected by the reflected light LR particularly around theedges of the pixel electrode 15.

In the VA mode, an oblique electric field, generated in the vicinity ofthe edge portions of the pixel electrode 15, has influence on the tiltdirections of liquid crystal molecules. For that reason, unless theoptical alignment treatment on those edge portions of the pixelelectrode 15 got stabilized, the display quality would deteriorate. Forexample, in the VATN mode (RTN mode) disclosed in Japanese PatentApplication No. 2005-169423, which was filed by the applicant of thepresent application, a dark line (i.e., a domain line), which isproduced in an area where the direction of the oblique electric field atthe edge portions of the pixel electrode and the pretilt directiondefined by the alignment film are different from each other (i.e., inthe vicinity of the edge of the right-hand-side portion of the pixelelectrode 15 shown in FIG. 1), penetrates deep into a pixel (i.e.,shifts toward the center of the pixel). Also, if the multi-domainstructure is adopted, a similar defect will occur not just in the edgeportions but also in the vicinity of a domain boundary around the centerof a pixel.

That is why to overcome such a reflected light problem, the intensity ofthe UV ray needs to be decreased sufficiently by the short waveabsorbing resin layer 14 that is arranged between the optical alignmentfilm 16 and the metal layer 12. However, if the thickness of the shortwave absorbing resin layer 14 exceeded 5 μm, a significant parallax(i.e., influence of the oblique incidence) would be produced due to thethickness of the short wave absorbing resin layer 14. Nevertheless, ifthe thickness of the short wave absorbing resin layer 14 were less than1 μm, then it would be difficult to deposit that thin short waveabsorbing resin layer 14 just as intended. For these reasons, the shortwave absorbing resin layer 14 preferably has a thickness of 1 μm to 5μm. Furthermore, as visible radiation for use in a display operationalso passes through the short wave absorbing resin layer 14, the shortwave absorbing resin layer 14 preferably exhibits high transmittancewith respect to the visible radiation. Specifically, the short waveabsorbing resin layer 14 preferably has a transmittance of at least 80%,and more preferably 90% or more, with respect to light falling withinthe wavelength range of 400 nm to 800 nm. The light emitted from abacklight for display purposes passes through the short wave absorbingresin layer 14 only once. For that reason, the “transmittance” refersherein to the transmittance of the short wave absorbing resin layer 14itself.

The results of our analysis on the transmittance with respect to a UVray will be described with reference to FIGS. 2 and 3. Specifically,FIG. 2 shows the transmittance spectra Ta and Tb of the two types ofshort wave absorbing resin layers that were used in this example (whichwill be referred to herein as “film a” and “film b”, respectively). Thedashed transmittance curves Ta′ and Tb′ show the results obtained whenthe thicknesses of the films that ended up with the solid transmittancecurves were doubled. In this case, the transmittance with respect to theUV ray at the photosensitive wavelength that would have a harmful effecton the alignment treatment of the optical alignment film is representedby the dashed transmittance curves of the films with the doubledthicknesses. On the other hand, the transmittance with respect to thevisible radiation may be estimated by the solid transmittance curves.

The film a was made of an acrylate resin with photosensitivity. On theother hand, the film b was made of a mixture of the acrylate resin forthe film a and a benzotriazole based UV sorbent. Both of these films hada thickness of 2 μm. Optionally, an organic material such asbenzophenone can be used effectively as the UV sorbent. As the opticalalignment film, a photodimerized one including cinnamoyl group (seeChemical Formula (1)) was used.

FIG. 3 shows the emission spectrum IO of a light source for use in theoptical alignment treatment and the intensity spectra Ia′ and Ib′ of thereflected light with the films a and b, respectively. Ia′ and Ib′ werecalculated as Ia′=IO×Ta′×0.9 and Ib′=IO×Tb′×0.9, respectively, where 0.9is the reflectance in a situation where the metal layer 12 is analuminum layer. Aluminum is one of the metals that have the highestreflectance of 90% with respect to a UV ray. In this case, thewavelength dispersion of the reflectance is not taken intoconsideration.

The results of the experiments revealed that even with the film a, thealignment state was not disturbed by the reflected light and a good VAmode LCD could be obtained. As for light irradiation conditions, a 10 mWP-polarized UV ray was cast for five seconds at an angle of incidence of40 degrees (and with an intensity of 50 mJ). As shown in FIG. 3, evenwhen the film a was used, the intensity Ia′ of the light at 315 nm couldbe decreased to 60% of IO. Thus, it can be seen that a resin layer thathas such an optical property as to decrease the intensity of the lightthat has been incident on the short wave absorbing resin layer 14 andthen reflected from the metal layer 12 at the photosensitive wavelengthto 60% or less may be used as the short wave absorbing resin layer 14.

Meanwhile, the transmittances of the films a and b with respect tovisible radiation (as represented by the solid curves in FIG. 2) wereboth 80% or more. But the film a is preferred to the film b because thefilm a has a transmittance of more than 90%, which is higher than thatof the film b, and would realize a brighter display.

In addition, the film a is made of a resin with photosensitivity, andtherefore, a contact hole that electrically connects the pixel electrode15 and the metal layer (e.g., the drain electrode layer of a TFT) 12together may be made by a photolithographic process, which isbeneficial.

A VA mode liquid crystal display device according to this preferredembodiment can be obtained by arranging a color filter substrate withrespect to the TFT substrate 10A such that these two substrates faceeach other with a liquid crystal material with negative dielectricanisotropy interposed between them. The color filter substrate typicallyincludes a glass substrate, a color filter layer that has been formed onthe glass substrate by depositing color resin layers (such as red, greenand blue resin layers) thereon, a black matrix made of a black resinlayer, a counter electrode, and an optical alignment film that isarranged on one side of the counter electrode that will face the liquidcrystal layer. Such a color filter substrate usually has no metal layerbetween the glass substrate and the optical alignment film, andtherefore, would not cause the reflected light problem described aboveduring the optical alignment treatment. However, if the black matrix ismade of a metal layer, for example, the short wave absorbing resin layeris also preferably provided between the metal layer and the opticalalignment film. As the color resin layers and the black resin layerabsorb UV rays, the ability of the short wave absorbing resin layer ofthe color filter substrate to decrease the photosensitive wavelength maybe lower than that of the short wave absorbing resin layer 14 of the TFTsubstrate.

Also, as described above, the optical alignment treatment is animportant process step in the manufacturing process of a VA mode LCDthat has a so-called “multi-domain structure” in which the opticalalignment film has at least two areas with mutually different pretiltdirections within a pixel. And the present invention is effectivelyapplicable to such an LCD. Among other things, the present invention isparticularly effectively applicable to a VATN mode LCD with amulti-domain structure as disclosed in Japanese Patent Application No.2005-169423.

On top of that, the short wave absorbing resin layer can absorb not justthe UV ray for use to perform the optical alignment treatment but also aUV ray included in the light emitted from a backlight and a UV rayincluded in the ambient light. That is why as in the LCD disclosed inPatent Document No. 6, the short wave absorbing resin layer 14 can alsominimize the optical deterioration of the optical alignment film andimprove its reliability.

The entire contents of Japanese Patent Application No. 2005-286033, onwhich the present application claims priority, and Japanese PatentApplications Nos. 2005-141846 and 2005-169423 mentioned above are allhereby incorporated by reference.

INDUSTRIAL APPLICABILITY

A liquid crystal display device according to the present invention canbe used effectively in a TV receiver or any other device that shouldhave improved display quality.

1. A liquid crystal display device comprising: a vertical alignmentliquid crystal layer; first and second substrates that face each otherwith the liquid crystal layer interposed between them; a firstelectrode, which is arranged on one surface of the first substrate so asto face the liquid crystal layer, and a second electrode, which isarranged on one surface of the second substrate so as to face the liquidcrystal layer; and a first alignment film, which is arranged on thefirst electrode so as to contact with the liquid crystal layer, and asecond alignment film, which is arranged on the second electrode so asto contact with the liquid crystal layer, wherein the first alignmentfilm has been subjected to an optical alignment treatment by irradiatinga first alignment film material, having a photosensitive wavelengthwithin the wavelength range of 250 nm to 380 nm, with light includingthe photosensitive wavelength, and wherein the device further includes:a metal layer arranged between the first alignment film and the firstsubstrate; and a first resin layer arranged between the metal layer andthe first alignment film, and wherein the first resin layer has anoptical property that attenuates the intensity of light, which has beenincident on the first resin layer and then reflected from the metallayer, to 60% or less at the photosensitive wavelength.